Modeling the mitigation of seawater intrusion by pumping of brackish water from the coastal aquifer of Wadi Ham, UAE

The control and management of seawater intrusion in coastal aquifers is a major challenge in the field of water resources management. Seawater intrusion is a major problem in the coastal aquifer of Wadi Ham, United Arab Emirates, caused by intensive groundwater abstraction from increased agricultural activities. This has caused the abandonment of salinized wells and ultimately affected farming activities and domestic water supply in the area. In this study, the 3D finite element groundwater flow and solute transport model is developed using FEFLOW to simulate pumping of brackish water from the intrusion zone to control seawater intrusion in the aquifer. The model was calibrated and validated with available records of groundwater levels and salinity distribution. Different simulation scenarios were conducted to obtain optimum pumping locations, rates as well as a number of wells. A comparison between scenarios of non-pumping and pumping of brackish water was conducted. Results showed an increase in the concentration of groundwater salinity under the non-pumping scenario, while it decreased under the pumping scenario. Under the non-pumping scenario, isoline 30,000 mgl⁻¹ was observed to have intruded into the south-eastern part of the aquifer, while the maximum isoline observed for the same area under the pumping scenario was 20,000 mgl⁻¹. This result showed an overall improvement in the quality of groundwater and ultimately halted seawater intrusion in the aquifer.